New PMP Question & Answers with explanation

Your project includes a new manufacturing technique that requires knowledge of chemical engineering to perform one of the services required in the project management plan. The service was performed, and as a result, an approved change request has been submitted. Which of the following statements is true?
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Nicolas is the project manager of a project that has been described as revolutionizing the mobile fitness tracking industry. He recently used his negotiation skills to achieve the support and agreement of two functional leads involved in his project. As part of his approach, he references the plan that outlines strategies and actions documented to manage specific stakeholders. What document did Nicolas reference to get this information?
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According to the PMBOK® Guide, this output of the Manage Stakeholder Engagement process is used to promote communication with stakeholders.
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There are 10 stakeholders within your project. As the project manager, you must therefore manage 45 communication channels. Two additional stakeholders have been added. How many more channels of communication must you manage?
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Who developed the model that defines the stages of a team’s development?
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